[java] multifaceted switch labels: basic highlighting (IDEA-196643)

2026-09-27 10:03:11 +07:00 · 2018-11-08 17:11:20 +01:00
parent 37e4af6d8a
commit dca9f4a33d
4 changed files with 88 additions and 45 deletions
@@ -46,6 +46,7 @@ import com.intellij.util.ArrayUtilRt;
 import com.intellij.util.JavaPsiConstructorUtil;
 import com.intellij.util.ObjectUtils;
 import com.intellij.util.containers.ContainerUtil;
+import com.intellij.util.containers.MultiMap;
 import com.intellij.util.containers.hash.HashSet;
 import com.intellij.util.ui.UIUtil;
 import com.intellij.xml.util.XmlStringUtil;
@@ -1850,63 +1851,78 @@ public class HighlightUtil extends HighlightUtilBase {
      return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(statement).descriptionAndTooltip(description).create();
    }

+    return null;
+  }
+
+  @Nullable
+  static Collection<HighlightInfo> checkSwitchLabelValues(@NotNull PsiSwitchStatement switchStatement) {
    PsiCodeBlock body = switchStatement.getBody();
    if (body == null) return null;

    PsiExpression switchExpression = switchStatement.getExpression();
    PsiType switchType = switchExpression == null ? PsiType.INT : switchExpression.getType();
-    boolean defaultCase = statement.isDefaultCase();
-    PsiExpression caseValue = statement.getCaseValue();
+    MultiMap<Object, PsiElement> values = new MultiMap<>();
+    Object defaultValue = new Object();
+    Collection<HighlightInfo> results = new ArrayList<>();

-    // Every case constant expression associated with a switch statement must be assignable ($5.2) to the type of the switch Expression.
-    if (caseValue != null && switchExpression != null) {
-      HighlightInfo highlightInfo = checkAssignability(switchType, caseValue.getType(), caseValue, caseValue);
-      if (highlightInfo != null) return highlightInfo;
-    }
-    Object value = null;
-    boolean isEnumSwitch = false;
-    if (!defaultCase && caseValue != null) {
-      if (caseValue instanceof PsiReferenceExpression) {
-        PsiElement element = ((PsiReferenceExpression)caseValue).resolve();
-        if (element instanceof PsiEnumConstant) {
-          isEnumSwitch = true;
-          value = ((PsiEnumConstant)element).getName();
-          if (((PsiReferenceExpression)caseValue).getQualifier() != null) {
-            String message = JavaErrorMessages.message("qualified.enum.constant.in.switch");
-            return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(caseValue).descriptionAndTooltip(message).create();
+    for (PsiStatement st : body.getStatements()) {
+      if (!(st instanceof PsiSwitchLabelStatementBase)) continue;
+      PsiSwitchLabelStatementBase labelStatement = (PsiSwitchLabelStatementBase)st;
+      boolean defaultCase = labelStatement.isDefaultCase();
+
+      if (defaultCase) {
+        values.putValue(defaultValue, ObjectUtils.notNull(labelStatement.getFirstChild(), labelStatement));
+      }
+      else {
+        PsiExpressionList expressionList = labelStatement.getCaseValues();
+        if (expressionList != null) {
+          for (PsiExpression expr : expressionList.getExpressions()) {
+            if (switchExpression != null) {
+              HighlightInfo result = checkAssignability(switchType, expr.getType(), expr, expr);
+              if (result != null) {
+                results.add(result);
+                continue;
+              }
+            }
+
+            Object value = null;
+            if (expr instanceof PsiReferenceExpression) {
+              PsiElement element = ((PsiReferenceExpression)expr).resolve();
+              if (element instanceof PsiEnumConstant) {
+                value = ((PsiEnumConstant)element).getName();
+                if (((PsiReferenceExpression)expr).getQualifier() != null) {
+                  String message = JavaErrorMessages.message("qualified.enum.constant.in.switch");
+                  results.add(HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(expr).descriptionAndTooltip(message).create());
+                  continue;
+                }
+              }
+            }
+            if (value == null) {
+              value = ConstantExpressionUtil.computeCastTo(expr, switchType);
+            }
+            if (value == null) {
+              String description = JavaErrorMessages.message("constant.expression.required");
+              results.add(HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(expr).descriptionAndTooltip(description).create());
+              continue;
+            }
+
+            values.putValue(value, expr);
          }
        }
      }
-      if (!isEnumSwitch) {
-        value = ConstantExpressionUtil.computeCastTo(caseValue, switchType);
-      }
-      if (value == null) {
-        String description = JavaErrorMessages.message("constant.expression.required");
-        return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(caseValue).descriptionAndTooltip(description).create();
+    }
+
+    for (Map.Entry<Object, Collection<PsiElement>> entry : values.entrySet()) {
+      if (entry.getValue().size() > 1) {
+        Object value = entry.getKey();
+        String description = value == defaultValue ? JavaErrorMessages.message("duplicate.default.switch.label") : JavaErrorMessages.message("duplicate.switch.label", value);
+        for (PsiElement element : entry.getValue()) {
+          results.add(HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(element).descriptionAndTooltip(description).create());
+        }
      }
    }

-    // check duplicate
-    for (PsiStatement st : body.getStatements()) {
-      if (st == statement || !(st instanceof PsiSwitchLabelStatementBase)) continue;
-      PsiSwitchLabelStatementBase labelStatement = (PsiSwitchLabelStatementBase)st;
-      if (labelStatement.isDefaultCase() != defaultCase) continue;
-      PsiExpression caseExpr = labelStatement.getCaseValue();
-      if (isEnumSwitch && caseExpr instanceof PsiReferenceExpression) {
-        PsiElement element = ((PsiReferenceExpression)caseExpr).resolve();
-        if (!(element instanceof PsiEnumConstant && Comparing.equal(((PsiEnumConstant)element).getName(), value))) continue;
-      }
-      else {
-        // not assignable error already caught
-        if (!TypeConversionUtil.areTypesAssignmentCompatible(switchType, caseExpr)) continue;
-        if (!Comparing.equal(ConstantExpressionUtil.computeCastTo(caseExpr, switchType), value)) continue;
-      }
-      String description = defaultCase ? JavaErrorMessages.message("duplicate.default.switch.label") : JavaErrorMessages.message("duplicate.switch.label", value);
-      PsiElement element = caseValue != null ? caseValue : ObjectUtils.notNull(statement.getFirstChild(), statement);
-      return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(element).descriptionAndTooltip(description).create();
-    }
-
-    return null;
+    return results;
  }


@@ -2433,6 +2449,16 @@ public class HighlightUtil extends HighlightUtilBase {
          }
          classicLabels = true;
        }
+
+        if (!levelChecked && element instanceof PsiSwitchLabelStatementBase) {
+          PsiExpressionList values = ((PsiSwitchLabelStatementBase)element).getCaseValues();
+          if (values != null && values.getExpressionCount() > 1) {
+            HighlightInfo info = checkFeature(values, Feature.ENHANCED_SWITCH, languageLevel, file);
+            if (info != null) return info;
+            levelChecked = true;
+          }
+        }
+
        element = PsiTreeUtil.skipWhitespacesAndCommentsForward(element);
      }
      if (alien != null) {
@@ -1595,6 +1595,7 @@ public class HighlightVisitorImpl extends JavaElementVisitor implements Highligh
    super.visitSwitchStatement(statement);
    if (!myHolder.hasErrorResults()) myHolder.add(HighlightUtil.checkSwitchBlockStatements(statement, myLanguageLevel, myFile));
    if (!myHolder.hasErrorResults()) myHolder.add(HighlightUtil.checkSwitchSelectorType(statement, myLanguageLevel));
+    if (!myHolder.hasErrorResults()) myHolder.addAll(HighlightUtil.checkSwitchLabelValues(statement));
  }

  @Override
@@ -59,6 +59,19 @@ class EnhancedSwitchStatements {

    switch (E.valueOf("E1")) {
      case <error descr="Constant expression required">null</error> -> noop();
+      case <error descr="An enum switch case label must be the unqualified name of an enumeration constant">E.E1</error> -> noop();
+      case E2 -> noop();
+    }
+
+    switch (new Random().nextInt()) {
+      case <error descr="Duplicate label '1'">1</error>, <error descr="Duplicate label '1'">1</error> -> noop();
+    }
+
+    switch (new Random().nextInt()) {
+      case 1, <error descr="Duplicate label '2'">2</error>:
+        noop(); break;
+      case 3, <error descr="Duplicate label '2'">2</error>:
+        noop(); break;
    }
  }

@@ -29,6 +29,9 @@ class UnsupportedFeatures {
      <error descr="Enhanced 'switch' blocks are not supported at language level '6'">case 0 -> throw new IllegalStateException("empty list");</error>
      default -> System.out.println("it's okay");
    }
+    switch (list.size()) {
+      case <error descr="Enhanced 'switch' blocks are not supported at language level '6'">1, 2</error>:
+    }
  }

  void f(<error descr="Receiver parameters are not supported at language level '6'">Object this</error>) { }